5-Series (E12,E28, E34, E39, E60)Chat relating to the BMW 5-Series of all generations. Specific models include: BMW 518, BMW 520, BMW 520i, BMW 530i, BMW 528i, BMW 530i, BMW 518i, BMW 524d, BMW 525i, BMW 525e, BMW 528e, BMW 540i, BMW 535i, BMW 520d, BMW 525td, BMW 525d, BMW 530d, BMW 525i/xi, BMW 530i/xi. (BMW 5-Series Forum)
I need ur help,
Ive got a 97 528i manual. It started to overheat about 4 months ago and was diagnosed as a thermostat, so i changed the thermostat, housing and vicscous. I made the mistake of not changing the waterpump, Now 3 months on the car runs lovely but the heating kicks in on passenger side first and then slowly makes its way to drivers side, now intermittently only when in slow traffic the car will overheat, and the tell tale sign is that the heating will cut out, but ive noticed if at standstill you rev the engine to 3,000 revs for around 30 seconds temp will come back down and heating will kick back in, apart fromn that the car drives fine, now noticed the other day after a 4 mile journey when i got home and opened the bonnet, that top hose was hot and bottom was cold, ive noticed that my ext pusher fan isnt kickin in even when the air cons on so i take it thats the temp switch on the side of the rad. If anyone know which pins to jumper or supply a live to in order to test it that would be great, I need your help on this one, could it be the waterpump or is it something else,
I agree with witeshark...... a bleed is necessary!
It really helps to have a friend lend a hand by sitting in the car revving the engine and keeping an eye on the temp gauge. Start off by removing the coolant reservoir cap and the plastic bleeder screw right next to it. Fill the coolant reservoir with a 50/50 mix of coolant and distilled water. Have your friend start the car, turn on the heater to full hot on the vent position and rev the engine to about 2500 RPM, if the temp gauge goes past the 12 o'clock position, shut the engine off, let it cool down and start over again. Watch the coolant reservoir, as the engine warms up the coolant level should drop, refill as the coolant is sucked out of the reservoir. Watch the bleeder screw hole also, when coolant with no air bubbles begins to overflow then you're almost done. It's a good idea to have some paper towels handy to mop up any overflow. Screw the bleeder screw back in (be careful to not break the plastic screw) and continue to rev the engine, you should see a continuous stream of coolant spraying in to the reservoir from the small hole at the top. Continue letting that spray in to the reservoir while your friend revs the engine for a couple of minutes, until the gauge hits the 12 o'clock mark, to ensure any remaining air is gone. If the heater is blowing hot air when you're revving the motor AND when the engine is at idle then your cooling system is properly bled. If your vents are blowing cool air at idle then you still have air in the system, try revving the engine more and/or squeeze the radiator hoses to help dislodge any trapped air. Once your system is fully bled, top off the reservoir and replace the cap. Check the coolant level in a day or two and top off as needed.
Your fan should come on anytime your air conditioning is running. If it doesn't, chances are that the fan is bad. Some fans are two-speed and you can jumper for low or high. When I checked mine, neither one would work and I ordered a new fan from BAV Auto. Car runs cool now, even in the hottest Texas weather. Good luck.
The pusher fan has very little or nothing to do with your car over heat. If bleeding don't work, you may have to change thermostat and water pump just to be safe.
BTW, you can direct inject 12V dc to Brown (negative) against other to to check for fan functions. My guess would be the resistor pack inside the fan ass'y, they are known for short live.
If you're familiar with electrical circuit, then you can by pass the resistor and check for fan motor, you can only do this only if the fan ass'y is removed.
Had the exact same problem in O6. I came up with a leak on the waterpump. Which I checked about a zillion time. The leak around the pump is hard to find because by the time you look under hood the fluids have already dried-up cause the enginge is hot. tighten the screws up and then see what what happens. And don't forget to bleed
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